Yes

you do need a jacket based on the weather in Seattle, WA 98115, USA 1 second ago

Why? Because it's not very warm out!
58°F15°C & Mostly Clear

Wind is 4 mph6 km/h from the North, gusting to 10 mph16 km/h
June 5
3am57°F14°C4 mph6 km/h NorthMostly Clear
4am56°F13°C2 mph4 km/h NortheastMostly Clear
5am55°F13°C2 mph3 km/h NortheastMostly Clear
6am54°F12°C3 mph4 km/h NorthMostly Clear
7am54°F12°C2 mph4 km/h NorthPartly Cloudy
8am53°F12°C2 mph3 km/h NortheastMostly Clear
9am54°F12°C1 mph2 km/h NorthMostly Clear
10am56°F13°C2 mph4 km/h NorthMostly Clear
11am58°F15°C3 mph5 km/h NorthClear
12pm61°F16°C4 mph6 km/h NorthMostly Clear
1pm64°F18°C5 mph8 km/h NorthMostly Clear
2pm67°F19°C6 mph10 km/h NorthClear
DateLowHighWindDayNight
June 453°F12°C69°F21°C2 mph3 km/h from SouthwestMostly CloudyMostly Clear
June 553°F12°C75°F24°C7 mph11 km/h from NorthMostly ClearMostly Cloudy
June 656°F14°C77°F25°C5 mph7 km/h from NorthwestPartly CloudyPartly Cloudy
June 756°F13°C77°F25°C6 mph10 km/h from NorthClearClear
June 858°F15°C81°F27°C5 mph8 km/h from NorthwestClearClear
June 960°F16°C79°F26°C6 mph10 km/h from NorthwestClearMostly Clear
June 1058°F14°C77°F25°C4 mph6 km/h from SouthwestMostly ClearMostly Clear

Yes

Low of 53°F12°C, High of 74°F24°C
Wind: 7 mph11 km/h
Precipitation: None

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